91 lines
3.2 KiB
C++
91 lines
3.2 KiB
C++
// GrovePi Example for using the analog write
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// http://dexterindustries.com/grovepi
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/*
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## License
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The MIT License (MIT)
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GrovePi for the Raspberry Pi: an open source platform for connecting Grove Sensors to the Raspberry Pi.
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Copyright (C) 2017 Dexter Industries
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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THE SOFTWARE.
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*/
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#include "grovepi.h"
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using namespace GrovePi;
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// sudo g++ -Wall grovepi.cpp grovepi_analog_write.cpp -o grovepi_analog_write.out -> without grovepicpp package installed
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// sudo g++ -Wall -lgrovepicpp grovepi_analog_write.cpp -o grovepi_analog_write.out -> with grovepicpp package installed
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int main()
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{
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int pin = 3; // we use port D3
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// for direction = HIGH the value we write increases with each step
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// for direction = LOW the value we write decreases with each step
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int direction = HIGH;
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int increment_value = 3; // step increase for PWN function
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int final_value = 0; // variable to hold to value to write to GrovePi
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try
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{
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initGrovePi(); // initialize communication w/ GrovePi
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pinMode(pin, OUTPUT); // set the pin mode for writing
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// continuously do this
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while(true)
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{
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// iterate the whole range of values
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// 0 -> 255 maps to 0V -> VCC, where VCC is the supply voltage on GrovePi
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//
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// since we're using the a PWM function
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// we have a duty cycle that goes from 0% to 100% of VCC voltage
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// with an increase/decrease of voltage of 100 * increment_value / 256 = 0.39% / increment
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//
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// google what a PWM wave is
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for(int value = 0; value <= 255; value += increment_value)
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{
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final_value = 0; // reset it
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if(direction == HIGH)
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// if direction == HIGH then let the final_value take ascending values
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final_value = value;
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else if(direction == LOW)
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// if direction == LOW then let the final_value take descending values
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final_value = 255 - value;
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printf("[pin %d][analog write = %d]\n", pin, final_value);
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analogWrite(pin, final_value);
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delay(5); // wait 5 ms for the next change in pin value
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}
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// if increment_value = HIGH then change it to increment_value = LOW
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// if increment_value = LOW then change it to increment_value = HIGH
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direction = (direction == HIGH) ? LOW : HIGH;
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}
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}
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catch (I2CError &error)
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{
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printf(error.detail());
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return -1;
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}
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return 0;
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}
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